Accuracy of predictive scores of hemorrhagic transformation in patients with acute ischemic stroke

Traditional and machine learning models for predicting haemorrhagic transformation in ischaemic stroke: a systematic review and meta-analysis

BACKGROUND

Haemorrhagic transformation (HT) is a severe complication after ischaemic stroke, but identifying patients at high risks remains challenging. Although numerous prediction models have been developed for HT following thrombolysis, thrombectomy, or spontaneous occurrence, a comprehensive summary is lacking. This study aimed to review and compare traditional and machine learning-based HT prediction models, focusing on their development, validation, and diagnostic accuracy.

METHODS

PubMed and Ovid-Embase were searched for observational studies or randomised controlled trials related to traditional or machine learning-based models. Data were extracted according to Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS) checklist and risk of bias was assessed using the Prediction model Risk Of Bias ASsessment Tool (PROBAST). Performance data for prediction models that were externally validated at least twice and showed low risk of bias were meta-analysed.

RESULTS

A total of 100 studies were included, with 67 focusing on model development and 33 on model validation. Among 67 model development studies, 44 were traditional model studies involving 47 prediction models (with National Institutes of Health Stroke Scale score being the most frequently used predictor in 35 models), and 23 studies focused on machine learning prediction models (with support vector machines being the most common algorithm, used in 10 models). The 33 validation studies externally validated 34 traditional prediction models. Regarding study quality, 26 studies were assessed as having a low risk of bias, 11 as unclear, and 63 as high risk of bias. Meta-analysis of 15 studies validating eight models showed a pooled area under the receiver operating characteristic curve of approximately 0.70 for predicting HT.

CONCLUSION

While significant progress has been made in developing HT prediction models, both traditional and machine learning-based models still have limitations in methodological rigour, predictive accuracy, and clinical applicability. Future models should undergo more rigorous validation, adhere to standardised reporting frameworks, and prioritise predictors that are both statistically significant and clinically meaningful. Collaborative efforts across research groups are essential for validating these models in diverse populations and improving their broader applicability in clinical practice.

SYSTEMATIC REVIEW REGISTRATION

International Prospective Register of Systematic Reviews (CRD42022332816).

[Cerebrolysin and the optimal timing of anticoagulation resumption in stroke: combined post hoc survival analysis of the CEREHETIS trial]

OBJECTIVE

To evaluate the effect of Cerebrolysin on hazard dynamics of hemorrhagic transformation (HT) and identify optimal anticoagulation therapy (AT) resumption timing in stroke patients, stratified by the Hemorrhagic Transformation Index (HTI).

MATERIAL AND METHODS

A post hoc survival analysis of the CEREHETIS trial (ISRCTN87656744) included patients with middle cerebral artery infarctions. The intervention group (IG, n=91) received Cerebrolysin with intravenous thrombolysis (IVT) and standard care, while the control group (CG, n=147) received IVT and standard care alone. Additionally, a validation cohort (VC, n=248) from an observational study was analyzed. Patients were stratified into low-risk (HT=0), high-risk (HTI=1-4), and very-high-risk (HTI=5-8, VC only) groups. Symptomatic HT and any HT within 14 days post-stroke were defined as failure events. Hazard dynamics were modeled using a Gompertz parametric survival approach, with a hazard threshold (0.6% per day) estimating safe AT resumption timing.

RESULTS

Cerebrolysin significantly reduced risk of symptomatic HT (HR 0.245; 95% CI 0.072-0.837; p=0.02) and any HT (HR 0.543; 95% CI 0.297-0.991; p=0.032). The compounding effect peaked on day 1 and persisted through days 7-10 in very-high-risk patients (HTI=5-8). In high-risk patients (HTI=1-4), Cerebrolysin mitigated the compounding effect and reduced hazard levels to the threshold by day 2, compared to days 3-5 in the CG and VC. The hazardous period extended to day 10 in HTI=5-8. In low-risk patients (HTI=0), hazard levels remained below the threshold from day 1, with no measurable impact of Cerebrolysin on HT.

CONCLUSION

AT may be safely resumed within 48 h in low-risk patients (HTI=0), on days 3-5 in high-risk patients (HTI=1-4), and on day 10 in very-high-risk patients (HTI=5-8) without symptomatic HT. Cerebrolysin mitigates the compounding effect, reduces HT risk, and facilitates earlier, safer AT resumption in high-risk patients (HTI=1-4) by day 2 post-stroke, supporting its role in personalized stroke management.

Hemorrhagic transformation after thrombolytic therapy for acute ischemic stroke: Accuracy and improvement of existing predictive models in a rural population of the Midwest

BACKGROUND

Hemorrhagic transformation (HT) after rtPA in acute ischemic stroke is a known complication of thrombolytic therapy. Several grading scales have been introduced in clinical practice, aiming to quantify the risk of HT before rtPA is administered. The goals of this study are to evaluate the performance of existing grading scales in a rural population of the Midwest and improve the existing models.

METHODS

This is a retrospective study of stroke patients treated with thrombolytics at Southern Illinois Healthcare from July 2017 to August 2024. Demographics, clinical presentations, laboratory values, neuroimaging, and stroke metrics were collected. HT found on neuroimaging within 24 h after rtPA was reviewed. mRS at 30 days was noted. The cohort was divided in two groups: HT and no-HT. The two groups were compared by univariate analyses. SEDAN, HAT, MSS, and THRIVE scores were calculated, and multivariable logistic regression analysis was run for each model. Area under the receiver operating characteristic curve (AUC) with its 95 % confidence interval was calculated for each grading scale. P value was set at 0.05.

RESULTS

Out of 279 patients included in this study, HT occurred in 8.6 % of patients (n = 24), whereas 91.4 % (n = 255) had no-HT. The two groups were similar in baseline characteristics and stroke severity. HT group had significantly worse mRS 0-2 at 30 days (42 % vs. 69 %, p < 0.05). SEDAN score demonstrated the highest accuracy in predicting HT after rtPA (AUC = 0.65, 95 % CI:0.56-0.75). Adding 1 point for smoking to the score, SEDAN-S, improved the accuracy of the model (AUC = 0.67, 95 % CI:0.57-0.77).

CONCLUSIONS

Existing predictive scales of HT after rtPA underperform in our rural population. Among those, SEDAN score is the most accurate predictor. Adding smoking status to the score improves its accuracy. Further larger studies in similar rural populations should be performed to confirm our results.

Heterogeneous treatment effects of Cerebrolysin as an early add-on to reperfusion therapy: post hoc analysis of the CEREHETIS trial

Background: There has been intensive research into enhancing the effects of reperfusion therapy to mitigate hemorrhagic transformation (HT) in stroke patients. Using neuroprotective agents alongside intravenous thrombolysis (IVT) appears a promising approach. Cerebrolysin is one of the candidates since it consists of neuropeptides mimicking the action of neurotrophic factors on brain protection and repair. Objectives: We looked at treatment effects of Cerebrolysin as an early add-on to IVT in stroke patients with varying HT risk. Methods: It was post hoc analysis of the CEREHETIS trial (ISRCTN87656744). Patients with middle cerebral artery infarction (n = 238) were selected from the intention-to-treat population. To stratify participants according to their HT risk, the DRAGON, SEDAN and HTI scores were computed for each eligible subject using on-admission data. The study endpoints were any and symptomatic HT, and functional outcome measured with the modified Rankin Scale (mRS) on day 90. Favorable functional outcome (FFO) was defined as an mRS ≤2. The performance of each stratification tool was estimated with regression approaches. Heterogeneous treatment effect analysis was conducted using techniques of meta-analysis and the matching-smoothing method. Results: The HTI score outperformed other tools in terms of HT risk stratification. Heterogeneity of Cerebrolysin treatment effects was moderate (I2, 35.8%-56.7%; H2, 1.56-2.31) and mild (I2, 10.9%; H2, 1.12) for symptomatic and any HT, respectively. A significant positive impact of Cerebrolysin on HT and functional outcome was observed in the moderate (HTI = 1) and high (HTI ≥2) HT risk patients, but it was neutral in those with the low (HTI = 0) risk. In particular, there was a steady decline in the rate of symptomatic (HTI = 0 vs. HTI = 4: by 4.3%, p = 0.077 vs. 21.1%, p < 0.001) and any HT (HTI = 0 vs. HTI = 4: by 1.2%, p = 0.737 vs. 32.7%, p < 0.001). Likewise, an mRS score reduction (HTI = 0 vs. HTI = 4: by 1.8%, p = 0.903 vs. 126%, p < 0.001) with a reciprocal increase of the fraction of FFO patients (HTI = 0 vs. HTI = 4: by 1.2% p = 0.757 vs. 35.5%, p < 0.001) was found. Conclusion: Clinically meaningful heterogeneity of Cerebrolysin treatment effects on HT and functional outcome was established in stroke patients. The beneficial effects were significant in those whose estimated on-admission HT risk was either moderate or high.

[Cerebrolysin as an early add-on to reperfusion therapy: heterogeneous treatment effect analysis in ischemic stroke patients with varying risk of hemorrhagic transformation]

OBJECTIVE

The study goal was the assessment of heterogeneous treatment effects of Cerebrolysin as an early add-on to reperfusion therapy in stroke patients with varying risk of hemorrhagic transformation (HT).

MATERIAL AND METHODS

It was post hoc analysis of the CEREHETIS trial (ISRCTN87656744). Patients with middle cerebral artery infarction (n=238) were stratified by HT risk with the HTI score. The study outcomes were symptomatic and any HT, and functional outcome measured with the modified Rankin Scale (mRS) on day 90. Favorable outcome was defined as an mRS score of ≤2. Heterogeneous treatment effect analysis was performed using techniques of meta-analysis and the matching-smoothing method.

RESULTS

Heterogeneity of Cerebrolysin treatment effects was moderate (I2=36.98-69.3%, H2=1.59-3.26) and mild (I2=18.33-32.39%, H2=1.22-1.48) for symptomatic and any HT, respectively. A positive impact of the Cerebrolysin treatment on HT and functional outcome was observed in patients with moderate (HTI=1) and high (HTI≥2) HT risk. However, the effect was neutral in those with low risk (HTI=0). In high HT risk patients, there was a steady decline in the rate of symptomatic (HTI=0 vs. HTI≥2: by 3.8%, p=0.120 vs. 14.3%, p<0.001) and any HT (HTI=0 vs. HTI≥2: by 0.6%, p=0.864 vs. 19.5%, p<0.001). Likewise, Cerebrolysin treatment resulted in an overall decrease in the mRS scores (HTI=0 vs. HTI≥2: by 2.1%, p=0.893 vs. 63%, p<0.001) with a reciprocal increase of the fraction with favorable outcome (HTI=0 vs. HTI≥2: by 2% p=0.634 vs. 19.2%, p<0.001).

CONCLUSION

Clinically meaningful heterogeneity of Cerebrolysin treatment effects on HT and functional outcome was established in stroke patients. The Cerebrolysin positive impact was significant in those whose estimated on-admission HT risk was either moderate or high.

Serum biomarkers to predict hemorrhagic transformation and ischemic stroke outcomes in a prospective cohort study

Ischemic stroke (IS) remains one of the most frequent causes of death and disability worldwide. Identifying possible prognosis factors for IS outcomes, including hemorrhagic transformation (HT), could improve patients' recovery. This study aimed to investigate the potential prognosis role of non-specific laboratory data at admission and baseline MMP-2 and MMP-9 serum levels in predicting HT risk, discharge, and 3-month follow-up status of IS patients. Data from 150 successive acute cerebral infarction patients were analyzed in a prospective cohort study. The active group included patients who developed HT during hospitalization (55 persons). There were no significant differences in age, gender distribution, time to admission, or time to blood sample collection for MMPs measurement between patients in the active and control groups. IS patients from the active group had a significantly higher rate of AF (atrial fibrillation) in the past (p=0.003), while differences in other factors such as diabetes, hypertension, myocardial infarction, previous stroke, obesity, smoking, and alcohol were not significant. Admission NIHSS score and mRS (modified Rankin Scale) values (at discharge and 90 days) were significantly worse in the active group (p<0.001). Among the analyzed admission laboratory factors (glycemia, lipid profile, coagulation panel, inflammatory reaction parameters, MMP-2, MMP-9), INR presented an inverse correlation, with lower values in the HT cohort (univariate analysis - p=0.01, OR=0.11; multivariate analysis - p=0.03, OR=0.09). Further research on larger cohorts is warranted to determine the specific laboratory biomarkers for predicting hemorrhagic transformation and ischemic stroke outcomes.

Proposal of multimodal computed tomography-based scoring system in prediction of hemorrhagic transformation in acute ischemic stroke

INTRODUCTION

The routinely used computed tomography (CT)-based workup in the setting of acute ischemic stroke (AIS) includes non-contrast brain CT, CT angiography (CTA), and CT perfusion. Several CT, CTA, CTP-based radiological biomarkers of hemorrhagic transformation (HT) were reported.

AIM OF THE STUDY

To assess the predictive value of the combined multimodal CT parameters for HT after AIS and proposal of predictive scoring scale.

METHODS

The source images of the NCCT, CTA and CTP of 282 AIS patients involving the anterior circulation (HT = 91, non-HT = 191) were retrospectively reviewed and the following biomarkers were recorded and analyzed: Early subtle ischemic signs, hyperdense middle cerebral artery sign (HMCAS) and Alberta Stroke Program Early CT Score (ASPECTS) < 7 in NCCT, large-vessel occlusion (LVO), clot burden score (CBS) < 6, large-vessel occlusion, poor collateral score (CS) and Tmax > 6 s ≥ 56.5 ml. A scoring system to predict HT based on these biomarkers was developed. Each biomarker counts for a single point with the total score ranging from 0 to 7.

RESULTS

All the aforementioned multimodal CT biomarkers and the selected cut offs were significantly associated with higher HT risk. The calculated scores were statistically significant different between the HT and the non-HT groups with AUC 0.761 (95% CI 0.703-0.819, P < 0.0000001). Rates of HT were approximately five times higher in patients with score ≥ 3.

CONCLUSION

Multimodal CT-based scoring system may provide highly reliable predictive model of hemorrhagic transformation in acute ischemic stroke.